1. Field of the Invention
The present invention relates to a sheet processing device, an image forming system, and a control program for a sheet processing device.
2. Description of the Related Art
In recent years, there have been known sheet processing devices that include a sheet processing mechanism (hereafter, referred to as the “stitching processing unit”) that stitches the stacked bundle of sheets. To stitch a bundle of sheets, the above sheet processing device moves the stitching processing unit to the target position and stitches the bundle of sheets at that position. However, in this type of sheet processing device, the natural vibration occurs when the stitching processing unit is moved.
Therefore, this type of sheet processing device has a problem in that noise occurs due to the movement of the stitching processing unit. Furthermore, in this sheet processing device, if sheet processing is conducted while vibrations occur due to the movement of the stitching processing unit, the sheet processing accuracy is degraded; therefore, there is a need to delay the start of processing on the subsequent sheet until the vibrations disappear, and there is a problem of a decrease in the productivity. Moreover, the above sheet processing device may have various problems due to the natural vibration that occurs when the stitching processing unit is moved.
Therefore, among the above-described sheet processing devices, a sheet processing device has been disclosed and already known, which controls the acceleration of the stitching processing unit so as to perform vibration control to prevent the natural vibration (for example, see Japanese Laid-open Patent Publication No. 2013-063831).
However, conventional sheet processing devices prevent the vibration by controlling the acceleration when the stitching processing unit is moved; therefore, the time during which the stitching processing unit is moved becomes accordingly longer, and the productivity is decreased. Therefore, if the sheet processing device does not control the acceleration of the stitching processing unit, the productivity may be improved; however, the vibration is increased due to the movement of the stitching processing unit.
As described above, with the conventional sheet processing devices, improvement in the productivity and prevention of the vibration have a trade-off relation, and there is a problem such that, if either one of them is given with priority, the other one is sacrificed.
Furthermore, this problem may also occur in a sheet processing device, which includes a punching unit that punches a sheet, when the punching unit is moved.
Furthermore, the above problem may also occur in a sheet processing device, which moves a sheet stack unit to adjust the level of a bundle of sheets and the level of a sheet conveyance path or to adjust the stack position of a bundle of sheets, when the sheet stack unit is moved.
Furthermore, the above problem may also occur in a sheet processing device, which moves a sheet ejecting unit while it is in contact with a bundle of sheets to eject a sheet, stacked on the sheet stack unit, when the sheet ejecting unit is moved.
Moreover, the above problem may also occur in a sheet processing device, which moves a pair of sheet aligning units such that they are opposed to each other with a bundle of sheets interposed therebetween in a sheet width direction so as to align the bundle of sheets, when the sheet aligning units are moved.
Therefore, there is a need to prevent the vibration that occurs when a sheet processing unit is moved.